Differences in visual search tasks between congenitally deaf and normally hearing adults

Do deaf people develop capacities of their remaining senses that exceed those of hearing individuals? Are the compensatory effects due to attention-dependent strategies? We investigated these questions, using texture segmentation and visual search tasks. The advantage of these tasks is that they contain attention-dependent and attention-independent components. We investigated 8 hearing adult observers, and 99 hearing and 89 deaf subjects aged between 6 and 20 years. The subject's task was to search for a discrepant stimulus among a number of distracting items. We used four different visual search tasks (circles with and without a 90° gap; circles with and without an added vertical line; pairs of convergent and parallel lines; tilted and vertical single lines) and oriented textures containing either a single line or a group of 16 discrepant lines. Visual search and texture segmentation tasks were randomly intermingled. Each subject participated in eight experimental runs, on two consecutive days. Both groups of subjects showed consistent learning effects for all tasks. In both groups, reaction times for all tasks decreased with age and reached an optimum at about 16 – 18 years. However, statistical comparisons do not indicate compensatory effects for deafness: reaction times and error rates of the deaf subjects were higher than those of the age-matched hearing subjects, for both the serial and the parallel tasks. These results were independent of the age and gender of the subjects and occurred for all etiologies for deafness. These results suggest deficiencies in the visual processing capacity of deaf subjects in tasks with and without attentional load.

In this study, we applied a transcranial magnetic stimulation (TMS) to investigate the temporal aspect for the functional processing of visual attention. Although it has been known that right posterior parietal cortex (PPC) in the brain has a role in certain visual search tasks, there is little knowledge about the temporal aspect of this area. Three visual search tasks that have different difficulties of task execution individually were carried out. These three visual search tasks are the “easy feature task,” the “hard feature task,” and the “conjunction task.” To investigate the temporal aspect of the PPC involved in the visual search, we applied various stimulus onset asynchronies (SOAs) and measured the reaction time of the visual search. The magnetic stimulation was applied on the right PPC or the left PPC by the figure-eight coil. The results show that the reaction times of the hard feature task are longer than those of the easy feature task. When SOA=150 ms, compared with no-TMS condition, there was a significant increase in target-present reaction time when TMS pulses were applied. We considered that the right PPC was involved in the visual search at about SOA=150 ms after visual stimulus presentation. The magnetic stimulation to the right PPC disturbed the processing of the visual search. However, the magnetic stimulation to the left PPC gives no effect on the processing of the visual search.

Measuring attention to traffic is common in pedestrian safety studies. However, little is known of how visual search patterns affect safe crossing decisions or to what pedestrians are actually attending....

BackgroundPatients with Alzheimer’s disease (AD) are known to exhibit visuospatial processing impairment, as reflected in eye movements from the early stages of the disease. We investigated whether the pattern of gaze exploration during visual tasks could be useful for detecting cognitive decline at the earliest stage.MethodsSixteen AD patients (age: 79.1 ± 7.9 years, Mini Mental State Examination [MMSE] score: 17.7 ± 5.3, mean ± standard deviation) and 16 control subjects (age: 79.4 ± 4.6, MMSE score: 26.9 ± 2.4) participated. In the visual memory task, subjects memorized presented line drawings for later recall. In the visual search tasks, they searched for a target Landolt ring of specific orientation (serial search task) or color (pop-out task) embedded among arrays of distractors. Using video-oculography, saccade parameters, patterns of gaze exploration, and pupil size change during task performance were recorded and compared between AD and control subjects.ResultsIn the visual memory task, the number of informative regions of interest (ROIs) fixated was significantly reduced in AD patients compared to control subjects. In the visual search task, AD patients took a significantly longer time and more saccades to detect the target in the serial but not in pop-out search. In both tasks, there was no significant difference in the saccade frequency and amplitude between groups. On-task pupil modulation during the serial search task was decreased in AD. The number of ROIs fixated in the visual memory task and search time and saccade numbers in the serial search task differentiated both groups of subjects with high sensitivity, whereas saccade parameters of pupil size modulation were effective in confirming normal cognition from cognitive decline with high specificity.DiscussionReduced fixation on informative ROIs reflected impaired attentional allocation. Increased search time and saccade numbers in the visual search task indicated inefficient visual processing. Decreased on-task pupil size during visual search suggested decreased pupil modulation with cognitive load in AD patients, reflecting impaired function of the locus coeruleus. When patients perform the combination of these tasks to visualize multiple aspects of visuospatial processing, cognitive decline can be detected at an early stage with high sensitivity and specificity and its progression be evaluated.

Dementia alters standing postural adaptation during a visual search task in older adult men

Peri-hand space is the area surrounding the hand. Objects within this space may be subject to increased visuospatial perception, increased attentional prioritization, and slower attentional disengagement compared to more distal objects. This may result from kinesthetic and visual feedback about the location of the hand that projects from the reach and grasp networks of the dorsal visual stream back to occipital visual areas, which in turn, refines cortical visual processing that can subsequently guide skilled motor actions. Thus, we hypothesized that visual stimuli that afford action, which are known to potentiate activity in the dorsal visual stream, would be associated with greater alterations in visual processing when presented near the hand. To test this, participants held their right hand near or far from a touchscreen that presented a visual array containing a single target object that differed from 11 distractor objects by orientation only. The target objects and their accompanying distractors either strongly afforded grasping or did not. Participants identified the target among the distractors by reaching out and touching it with their left index finger while eye-tracking was used to measure visual search times, target recognition times, and search accuracy. The results failed to support the theory of enhanced visual processing of graspable objects near the hand as participants were faster at recognizing graspable compared to non-graspable targets, regardless of the position of the right hand. The results are discussed in relation to the idea that, in addition to potentiating appropriate motor responses, object affordances may also potentiate early visual processes necessary for object recognition.

How Mammographic Breast Density Affects Radiologists' Visual Search Patterns

We examined timing and scanning paths of eye movements during a visual search task, in which subjects had to detect, as quickly as possible, the presence or absence of a target among distractors [Q-like element among O stimuli (QvsO) and vice-versa (OvsQ)]. According to an influential theory [Treisman, A. & Gelade, G. (1980) Cognitive Psychol, 12, 97--136; Treisman, A. & Sato, S. (1990) J. Exp. Psychol. Hum. Percept. Perform., 16, 459--478], only tasks yielding nonflat search functions (OvsQ) involve focal attention. Alternative models propose that all kinds of visual search are resolved by a biased competitive process, working in parallel across the visual field. Data show that QvsO and OvsQ tasks are characterized by quantitative rather than by qualitative differences in search strategy. No differences between the two tasks were found regarding either the percentage of saccades foveating single stimulus items or the timing of the button response with respect to the onset of the last foveation saccade within a trial. Furthermore, the number of saccades made during search predicted very accurately the time required to accomplish the task and fixation times were independent of the number of stimulus items. On the basis of our results there is no reason to postulate the occurrence of shifts of visuospatial attention, other than those associated with the executions of saccadic eye movements, which are driven by a parallel feature analysis of the visual scene, in both types of search tasks. A time-limited competitive model for attentive target identification, in which both parallel (competitive) and serial (attentive) processing mechanisms are integrated, can account for these findings, providing a unified conceptual framework for all kinds of visual search.

Visual search and visual lobe size: can training on one affect the other?

The hypothesis that visual search tasks requiring effortful, serial processing are more sensitive to aging than those requiring relatively automatic, parallel processing was tested in 96 healthy adults who performed parallel and serial visual search tasks with fixed presentation times. Reaction times and error rates increased with age in both tasks, but there was no difference between young and old in the effect of increasing numbers of distractors on reaction times. However, the older subjects made significantly more errors with increasing numbers of distractors in the serial search task. Older subjects have disproportionately more difficulty performing serial compared to parallel visual search tasks than do younger subjects. Additionally, this difference is not caused solely by cautious response strategies in the elders.

Breast cancer is the most common cancer among females worldwide and large volumes of breast images are produced and interpreted annually. As long as radiologists interpret these images, the diagnostic accuracy will be limited by human factors and both false-positive and false-negative errors might occur. By understanding visual search in breast images, we may be able to identify causes of diagnostic errors, find ways to reduce them, and also provide a better education to radiology residents. Many visual search studies in breast radiology have been devoted to mammography. These studies showed that 70% of missed lesions on mammograms attract radiologists' visual attention and that a plethora of different reasons, such as satisfaction of search, incorrect background sampling, and incorrect first impression can cause diagnostic errors in the interpretation of mammograms. Recently, highly accurate tools, which rely on both eye-tracking data and the content of the mammogram, have been proposed to provide feedback to the radiologists. Improving these tools and determining the optimal pathway to integrate them in the radiology workflow could be a possible line of future research. Moreover, in the past few years deep learning has led to improving diagnostic accuracy of computerized diagnostic tools and visual search studies will be required to understand how radiologists interact with the prompts from these tools, and to identify the best way to utilize them. Visual search in other breast imaging modalities, such as breast ultrasound and digital breast tomosynthesis, have so far received less attention, probably due to associated complexities of eye-tracking monitoring and analysing the data. For example, in digital breast tomosynthesis, scrolling through the image results in longer trials, adds a new factor to the study's complexity and makes calculation of gaze parameters more difficult. However, considering the wide utilization of three-dimensional imaging modalities, more visual search studies involving reading stack-view examinations are required in the future. To conclude, in the past few decades visual search studies provided extensive understanding about underlying reasons for diagnostic errors in breast radiology and characterized differences between experts' and novices' visual search patterns. Further visual search studies are required to investigate radiologists' interaction with relatively newer imaging modalities and artificial intelligence tools.

Visual search has traditionally been studied in cognitive and perceptual paradigms, but little is known about how it contributes to visuomotor performance. We have developed a novel computational model to examine how three underlying processes of visual search (spatial planning, working memory, and peripheral visual processing) contribute to visual search during a visuomotor task. We show that deficits integrating spatial planning and working memory underlie abnormal performance in stroke survivors with frontoparietal damage.

Studies have shown the possibility to classify user tasks from eye-movement data. We present a new way to determine the optimal model for different visual attention tasks using data that includes two types of visual search tasks, a visual exploration task, a blank screen task, and a task where a user needs to fixate at the center of any scene. We used deep learning and SVM models on RGB images generated from fixation scan paths from these tasks. We also used AdaBoost on filtered eye movement data as a baseline. Our study shows that deep learning gives the best accuracy for classifying between visual search tasks but misclassified between visual search and visual exploration tasks. Machine learning-based methods performed with high accuracy classifying tasks that involve minimal visual attention. Our study gives insight on the best model to choose by type of visual task using eye movement data.

Here, we ask which neural regions have neural response patterns that correlate with behavioral performance in a visual processing task. We found that the representational structure across all of high-level visual cortex has the requisite structure to predict behavior. Furthermore, when directly comparing different neural regions, we found that they all had highly similar category-level representational structures. These results point to a ubiquitous and uniform representational structure in high-level visual cortex underlying visual object processing.

Prior research has demonstrated that scene cues within real-world environments significantly expedite visual search tasks, particularly when co-occurrence objects—those that tend to appear concurrently and in close proximity—are present. The underlying mechanisms driving these enhancements remain a subject of ongoing debate. In this study, we recruited forty-five participants to perform a visual search task using real-world scene images, with conditions involving either the presence or absence of co-occurrence objects, while recording their right eye movements. Our findings revealed that the presence of co-occurrence objects exclusively enhanced search accuracy, without impacting response times or fixation durations. As participants engaged in repeated searches, their performance improved, characterized by increased accuracy, reduced response times, fewer fixations, and shorter fixation durations, applicable to both target objects and co-occurrence objects alike. Notably, the effect of co-occurrence objects remained consistent across search iterations, indicating no change with accumulated search experience. Collectively, these outcomes suggest a strategic role for co-occurrence objects in guiding visual search processes, potentially mediated through the spatial processing of target objects. This study contributes to our understanding of how contextual cues influence visual attention and search precision in complex environments.